Adjustable fore sight iris or trial and error with elements?

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tsokasn
Posts: 299
Joined: Tue Sep 11, 2007 12:22 am
Location: Athens,Hellas

Adjustable fore sight iris or trial and error with elements?

Post by tsokasn »

Hello everybody!
I shoot only indoors(for now)and I was working with the internal diameter of the foresight's element.Since now I was using a 4.0mm diam,and when I read a post about this topic ,I decided to try a 4.2mm(that was the only one I had...)I found it big and difficult to aim.So I return to 4.0mm.But I would like to try the 4.1mm and check it.What must I do?A Gehmann adjustable fore sight iris costs 71euros and gives lots of choices while a single element only 6euros.
What do you suggest?
peepsight
Posts: 479
Joined: Mon Sep 25, 2006 9:12 am
Location: London England

Adjustable fore sight

Post by peepsight »

If i remember rightly, you shoot a FWB which has a 22mm fore sight tunnel. I suggest you look at the CENTRA 22MM adjustable fore sight.
There are several models and some are available with a 1.6mm ring and some with a 2.0mm ring width. Check the range of adjustment that fits in with the size you like, such as 3.5 - 4.8.
Check their web site and choose carefully.
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Nick_Burman
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Location: Sao Paulo, Brazil

Post by Nick_Burman »

Tsokasn, can't you borrow elements from other shooters, just for trial? I found my settings using borroweed elements...

Cheers NB
tsokasn
Posts: 299
Joined: Tue Sep 11, 2007 12:22 am
Location: Athens,Hellas

Post by tsokasn »

peepsight
Thank you for your advice

Nick_Burman
I do my practise on evening hours,after my job and usually alone...Thank's anyway.
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Nick_Burman
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Location: Sao Paulo, Brazil

Post by Nick_Burman »

So do I, tsokasn... most of my shooting friends live away from the club, they tend to train at home. However I usually arrange to borrow something I want to test during a match and return it on the next match. Seldom fails...

Cheers NB
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pwh
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Location: Chicago, Ill.

Post by pwh »

Save some money and get the adjustable. I've had the Gehmann since about '79 and its great! I also shoot indoors 10 Meter. You have a handful of small increments from I believe 3.0 to 4.2. (at least with the one I have) Plenty of enough range of adjustments..... at least for me.

~Phil
robf
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Post by robf »

i've had an adjustable for a year, and whilst its good for experimenting, a foresight tunnel and a range of elements is probably cheaper.

pros of adjustable : easy to change, totally analogue ie you can have it set to 4.03 if you desire

cons : ring thickness (not diameter) has a minimum and this was too thick for my liking, temptation to fiddle rather than shoot.
GaryN
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Joined: Mon Mar 01, 2004 4:57 pm
Location: California

Post by GaryN »

Depends on what size your front sight is, 18mm or 22mm.

For 18mm, I got a set of inserts for 18mm that was MUCH cheaper than an adjustable. Once I figured out what size to use, it turned out that I use only 2 of them, depending on how bad my wobble is that day. If I'm more wobbly, I use the bigger insert.

The 22mm insert is more expensive, so based on my selection for my 18mm sight (FWB-300-mini), I got a similar size for the 22mm (FWB-P70-jr).

Based on the price difference, between the adjustable and the inserts, I use the inserts. I don't shoot serious competition for me to spend the extra for the adjustable. Heck I have an adjustable rear iris that once I figured what I want to use, I have not changed it.
Richard Blackburn

Adjustable foresights

Post by Richard Blackburn »

Some years ago I did a series of tests with foresight element sizes. I was helping to coach some male and female junior shooters (about 25 or 30 in the squad). They were all at a very good standard, training for prone, standing and kneeling shooting. All had good equipment.

We got them to shoot groups at 50m prone, putting different sizes of element in their foresights (metal elements for those who had them, or adjusting the element with those shooters who had adjustable foresights). The shooters didn't know the element sizes - we put them in for them. They then shot a series of groups on their targets (all in the same detail). We then measured the group sizes with a grouping gauge.

This test was repeated several times - each time the shooter got a different element size. It was outdoors, with very little wind and good light.

At the end of the test, which took quite a long time to run, we found that the considerable majority of people did better with the 3.8 element.

I've since repeated this test with other shooters, and the result has turned out the same.

It's worth remembering that these were junior shooters (say 18-20 years old), so their eyes would probably be better than older people (like me).

We also did the test with standing and kneeling. For kneeling, the best groups were still 3.8 (but 3.9 wasn't far off either). For standing, it was rather larger - about 4.2.

All the shooters in the test were experienced prone standing and kneeling shooters, so their overall performance was pretty good.

All the tests on the standard ISSF 50 m target, of course.

Richard
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